Why you should stop using Erlang97

Why you should stop using Erlang97

Many people in the contact center and workforce management industry still rely on the Excel 97 add-in to perform their Erlang calculations. However, the Erlang97 add-in is quite limited in its functionalities, and some of them are downright incorrect. For example, the service level calculation using a fractional number of agents is wrong. Erlang97 is simply insufficient for professional use, especially for workforce management in 2021. That is why CCmath has created an alternative to this outdated add-in which is future-proof and has added functions and parameters.

Erlang C is an obvious choice for single-skill inbound, but it lacks some crucial features. Furthermore, customer contact has changed enormously in the past twenty years. We now combine inbound and outbound, and communicate via chat, WhatsApp, and social media. In contrast to Erlang97, the new Erlang for Excel add-in does take these factors into account.

Less Erlang C, more Erlang X

In addition to the regular Erlang C functions, the Erlang for Excel add-in can perform Erlang X calculations, which are considerably more realistic. They allow abandonments and redials, thus improving the accuracy of your calculations. Contrary to Erlang97, the Erlang X functions factor in the effect of abandonments on later arrivals, and also differences in patience. Erlang97 assumes that everybody abandons after the same waiting time, which is evidently not what happens in practice.

Erlang X can also calculate service targets based on your service level, accessibility, or average speed of answer (ASA), as well as come up with maximum forecast volume, abandonment percentages, redial rates, and occupancy.

If you are working in a multi-skilled environment, Erlang C and Erlang X do have limitations. You need to have a simulation tool. Luckily, CCmath also developed OmniSim, the tool that helps you accurately size and optimize your agent pool. Read more about our OmniSim solution here.

What about blending?

The blending functions of the Erlang Calculator can blend inbound and outbound calls and perform the relevant capacity calculations. In addition to the SL and ASA capacity calculations, the add-in indicates how many outbound calls can be made with the available occupancy combined with the inbound volume and occupancy rates.

Erlang Chat?

Furthermore, the Erlang for Excel add-in provides important functionalities for chat channels. While many organizations apply Erlang C to chat, or manually correct for simultaneous skilling, the Erlang Chat functions can deal with the fact that different chats are often handled simultaneously, and that handling time increases with each additional concurrent chat.

Moreover, with the actual handling times and parameters for the simultaneity of the number of chats, the add-in can calculate the required capacity based on SL or ASA, plus the abandonment and occupancy rate. This makes the Erlang Calculator for Excel a one-of-a-kind add-in for workforce management and capacity planning.


Erlang97, thank you for helping us in the past, but the Erlang for Excel generation is here to stay. CCmath’s add-in is the one-stop solution for all your single-skill, blended, or chat capacity calculations. Are you interested in the Erlang Calculator for Excel? Please visit this page and start your free demo today.

If you want to learn more about our calculators, software, or training curriculum, please contact us via jesper@ccmath.com or this page.


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